1. Field of the Invention
The present invention relates in general to eyeglasses and auxiliary lenses capable of being detachably coupled to eyeglasses. More particularly, the present invention relates to means with which auxiliary lenses are attached to eyeglasses. And still more particularly, the present invention proposes a structure for the auxiliary lenses to form a secure connection when attached to the eyeglasses, without worry of falling apart from the eyeglasses due to slight change of shape of the frame of the eyeglasses when the eyeglasses fit on a human wearer's head.
2. Description of the Related Art
In the past various means have been utilized to secure auxiliary lenses to eyeglasses. One of them is clipping device, which is permanently attached to the auxiliary lenses. The clipping device fits around the frames of the eyeglasses to clip the auxiliary lenses to the eyeglasses. However, the clipping devices the eyeglasses look unattractive.
Another means for securing auxiliary lenses to eyeglasses is to use magnetic material. This is currently a popular way to secure auxiliary lenses to eyeglasses, and several devices have been proposed and patented, including Magnetic Means For Securing Auxiliary Lenses To Eyeglasses, patented by U.S. Patent and Trademark Office with U.S. Pat. No. 5,116,537, and Detachable Sunglasses With Magnets, also patented by U.S. Patent and Trademark Office with U.S. Pat. No. 5,642,177.
According to the above mentioned patents, U.S. Pat. Nos. 5,416,537 and 5,642,177, referring to FIGS. 6 and 7, magnets 101 are fixed to two end portions of rim 10 of the eyeglasses while magnets 201 are fixed to two end portions of rim 20 of the templeless auxiliary sunglasses; thus, the templeless auxiliary sunglasses can be secured to the eyeglasses by means of the magnets 201, 101 attracting each other to form a bond.
Another device proposed for the same purpose is a patent application with PCT, with application number WO 90/09611. Referring to FIG. 8, a magnet 302 is provided on bridge 301 of rim 30 of the eyeglasses while a second magnet 402 is mounted on bridge 401 of rim 40 of the templeless sunglasses; thus the templeless sunglasses can be secured to the eyeglasses by means of the magnets 402,302 attracting each other to form a bond.
However, through experience, it is found that the temples of the eyeglasses would broaden when fitting on a wearer's head, causing the end portions of the rim to angularly turn. The turning of the end portions of the rim would change the position of the magnets mounted thereon, resulting in loss of close contact between the magnets of the templeless sunglasses and the magnets of the eyeglasses and consequently the sunglasses fall from the eyeglasses under extreme conditions.
As for the sunglasses with magnets mounted on the bridge, the bond is found to be too weak and the sunglasses would easily turn at an angle from the desired position.
To overcome the disadvantages of the above mentioned means, other means have been proposed, including U.S. Patents Auxiliary Lenses For Eyeglasses, U.S. Pat. Nos. 5,568,207 and 5,737,054.
According to U.S. Pat. No. 5,568,207, referring to FIG. 10, magnets 503 are mounted on endpieces 502 of rim 50 of the eyeglasses, the endpieces 502 being provided to connect temples 501. Second magnets 602 are mounted on supporting end portions 601 of templeless sunglasses 60 so that the templeless sunglasses 60 can be secured to the eyeglasses by means of the bond between the magnets 503 and 602, the supporting end portions 601 resting on the endpieces 502 of the rim 50 to provide a stable support for the tempteless sunglasses 60, as shown in FIG. 11.
As for U.S. Pat. No. 5,737,054, Auxiliary Lenses For Eyeglasses, referring to FIG. 12, a magnet 702 is mounted on a bridge 701 of the eyeglasses 70 while a second magnet 803 is mounted on bottom portion of a protrusion 802 provided above a bridge of the templeless eyeglasses 80; thus, the templeless sunglasses can be secured to the eyeglasses by means of bond between the magnets 803 and 702 attracting each other.
Moreover, the inventor of the present invention proposed a means for securing auxiliary lenses to eyeglasses, which was filed at U.S. Patent and Trademark Office on Oct. 28, 1997 with application Ser. No. 08/959,486 referring to FIG. 13, magnets 901 are mounted on endpieces 902 of eyeglasses 90 in a way that recesses 903 are formed on the endpieces 902. A templeless eyeglasses 905 is provided, having extending portions 906 at two ends and magnets 904 mounted on the extending portions 906 in a way that the magnets 904 each forms a protrusion; thus, the templeless sunglasses 905 can be coupled to the eyeglasses by means of bond between the magnets 901 and 904 attracting each other, with the recesses 903 retaining the magnets 904 to strengthen the bond, as shown in FIG. 14.
The above mentioned three means provide a stabler and more secure connection between the eyeglasses and the templeless sunglasses, however the wearer has to put on the templeless sunglasses from above the eyeglasses fittings on his/her head due to presence of the extending portions 906 in FIG. 13, the protrusion 802 in FIG. 12, and the supporting end portions 601 in FIGS. 10 and 11. This is different from the way the wearer is used to when putting on the templeless sunglasses, i.e. from ahead of the eyeglasses. So it is not very convenient in using securing means of this kind.